Remove the SSD card.
Bash that card with a hammer, or other large tool, until the parts start flying.
And... your data is protected/gone. Well, still there, but no longer feasible to recover anything.
Too drastic?
Remove the SSD, install in an external enclosure that will take that card, connect to another Mac, and use Disk Utility to erase. I would probably reinstall some version of macOS on that card, without a user setup, then reinsert in the dead MBAir. (The reinstall will make ANY recovery of your old files extra-difficult, otherwise it serves no purpose, just what I would do)